design/optimization of heat/mass exchangers (hmx) using ... · • dr. kyle gluesenkamp and dr....

1U.S. DEPARTMENT OF ENERGY OFFICE OF ENERGY EFFICIENCY & RENEWABLE ENERGY

Design/Optimization of Heat/Mass Exchangers (HMX) using Membrane Technologies

Oak Ridge National LaboratoryVan D. Baxter, Distinguished R&D [email protected]


Project SummaryTimeline:Start date: 10/1/2017Planned end date: 9/30/2019Key Milestones1. Complete extension of ORNL HMX model to

three-fluid capability; March 31, 20182. Complete draft report on optimization case study

of sorption HPWH system using HMX model; August 31, 2018

3. Complete draft report on adaptation of HMX model for condensing membrane HX; June 30, 2019

Budget:Total Project: $350k thru FY18• DOE: $350k• Cost Share: $0

Total Project: $450k• DOE: $450k• Cost Share: $0

Key Partners:

Project Outcome: US residential and commercial buildings consumed 1.52 quads and 4.73 quads of natural gas for water heating and space heating, respectively, in 2017. A key goal noted in BTO’s 2016-2020 MYPP is development of advanced, heat-pump based gas systems to reduce gas SH and WH consumption. Early stage R&D is underway on several specific system developments. Robust, validated system simulation tools are needed to facilitate system design and optimization, a key step to eventual market entry. The FY18 goals of this supporting project are to develop and validate models of absorber components used in absorption heat pump systems and conduct a system design/optimization case study for one specific system (gas absorption HPWH).

Univ. of FL (UFL)

Ionic liquid (IL) desiccant property information & system data for model validation


Within DOE, ORNL is the Center of Excellence in Commercial and Residential building equipment R&D along with supporting analysis tool development.

Team members for this project include:• Dr. Zhiming Gao – Developer 2-fluid HMX model, leads

development of 3-fluid model & adaptation to condensing membrane HXs

• Dr. Moonis Ally – Consultant for HMX model• Dr. Bo Shen – Heat Pump Design model (HPDM) developer,

lead incorporation of HMX model into HPDM; co-lead system simulation & optimization

• Dr. Kyle Gluesenkamp and Dr. Ahmad Abu-Heiba – Sorption HPWH experts, coordinating with UFL for system test data and liquid desiccant properties data; co-lead system simulation & optimization

• Dr. Patrick Geoghegan – Sorption HPWH expert; model review; co-lead system simulation & optimization

• Van Baxter – Project manager, PI

Team


Challenge

Problem Definition: • US buildings consume 1.52 quads natural gas for

water heating (WH) and 4.73 for space heating (SH). • BTO’s 2016-2020 MYPP --- early stage R&D efforts

underway on gas heat pump based technologies. – 2020 targets: 1.38 SCOP for SH and 1.2 UEF for

sorption-based gas HPWHs (primary energy basis). – ~45% savings vs. 95% AFUE gas furnaces and Energy

Star gas storage WHs, respectively.• Membrane-based HPWH project (Moghaddam, 2017)

– Lab-measured 1.23 COP by prototype at UEF conditions.

Key need:• Validated, robust analytical tools for simulation and

design optimization of advanced systems.– Facilitate advancement to market readiness.

• FY18 goals of this early-stage supporting project– Develop/validate models of absorber & desorber.– Add to system model & conduct optimization case

study.

Membrane HPWHProduct concept

Semi-open absorption heat pump cycle diagram


Approach• In prior FY, the ORNL team developed a membrane-

based heat and mass exchanger (HMX) model for simulation of membrane dehumidification (DH) processes.

• In FY18, the project plan is to: – Extend 2-fluid DH model to enable simulation of

membrane-based HMX with 3-fluid streams (e.g., the absorber configuration for the Membrane-Based HPWH).

– Validate and refine the HMX component model vs. data from the current lab prototype membrane HPWH.

– Add HMX model to the ORNL Heat Pump Design Model (HPDM) for a case study membrane HPWH system design and optimization analysis.

Membrane-based HPWH prototype absorber/HX component (multiple, parallel absorber panels)Membrane-based 3-

Fluid HMX modeling Component-based system modeling platform


Progress• This supporting project began in FY18 but builds upon earlier

development of the initial two-fluid absorber HMX model.• The project is on track: The first milestone to complete

extension of the two-fluid model to three-fluid capability has been completed on schedule.

– Basic geometry schematic shown; source air stream is in crossflow, liquid desiccant and water can be in parallel or counter flow.

– Segment-by-segment simulation approach.• Each HX panel divided into small parallel segments; 2176 segments

used in sample case illustrated here (5x6 mm each).

– Model tested with sample data; achieved good mass & energy balances between the three fluid streams.

• Right: temperature difference across membrane (Tair-side – Tdes-side)• Below: air, desiccant, and water stream temperature profiles

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Air flow direction

IL desiccant direction

Water direction

Sample study:• 6 panels, each

0.34m*0.195m. • Inlet air: 22oC, 0.037kg/s and

50% RH; • Inlet ionic liquid (IL) desiccant:

23oC, 0.002 kg/s and 95% IL concentration;

• Inlet water: 15oC, 0.0075kg/s

Temperature difference between the membrane interface


Impact – Sorption HPWH and SH heat pumps

Most of the 6.25 quads of natural gas for buildings SH and WH (4.73+1.52) are presently consumed by gas-combustion furnaces and water heaters, respectively.

If advanced gas-based heat pump technologies with 45% energy savings replaced existing SH and WH stock overnight, the total potential source energy savings would be 2.8 quads/y. Even if the advanced technology captured only 10% of the market, savings would be 0.28 quads/yr.

• The availability of proven, robust gas heat pump analyses tools for system design and optimization is a key to facilitating development of market-ready gas heat pump products and progressing toward achieving this savings potential.

• This project is designed to advance gas heat pump system analyses tool development.


Stakeholder Engagement

Since this is a supporting model development project within the HVAC&R, WH, and Appliances subprogram intended to facilitate future industry collaborative activities for several gas heat pump based projects, the principal stakeholders are the BTO sponsor and PIs for those activities along with the HPDM developer. All are actively engaged in reviewing the HMX model development progress.


Remaining Project WorkRemaining FY18 work:• Test/validate HMX model vs. data from lab prototype membrane HPWH.• Incorporate HMX model into HPDM and conduct HPWH system optimization case

study analysis.

FY19 planned work:• Adapt HMX model to simulate condensing membrane HX.

– Support to membrane HX development under companion Furnace/Membrane project.• Motivation:

– Currently high efficiency (condensing) gas furnaces only account for ~25% of total US furnace shipments (Energy Star 2016 shipment data).

– Condensing membrane HX concept shows promise to reduce furnace costs with same high AFUEs (≥90%).

• Impact:– If cost reduction can enable condensing furnaces to capture an additional 25% of

shipments, energy savings impact would be about 0.17 quads/yr.– Proven, robust system simulation tools a key need to facilitate advanced development

in concert with manufacturer partners.


Thank You

Oak Ridge National LaboratoryVan D. Baxter, Distinguished R&D Staff

[email protected]

Reference: S. Moghaddam, “A Combined Water Heater Dehumidifier and Cooler,” presented at 2017 BTO Peer Review meeting: https://www.energy.gov/eere/buildings/downloads/combined-water-heater-dehumidifier-and-cooler-whdc

https://www.energy.gov/eere/buildings/downloads/combined-water-heater-dehumidifier-and-cooler-whdc


REFERENCE SLIDES


Project Budget: $450k total FY18019.Variances: None to date.Cost to Date: ~$116k through March 2018.Additional Funding: None.

Budget History

FY2018 FY2019(planned)

DOE Cost-share DOE Cost-share$350k $0 $100k $0

Project Budget


Project Plan and Schedule

Project ScheduleProject Start: October 1, 2017Projected End: September 30, 2019

Task

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Current/Future WorkQ2: complete 3- fluid HMX model extensionQ4: complete system design/opt case studyQ3: complete condensing membrane HX model

Completed WorkActive Task (in progress work)Milestone/Deliverable (Originally Planned) use for missed Milestone/Deliverable (Actual) use when met on time

FY2018 FY2019 FY2020

• Project start: 10/1/2018• Project planned completion date: 9/30/2019• Schedule and Milestones: see below

Sheet1

Project Schedule

Project Start: October 1, 2017Completed Work

Projected End: September 30, 2019Active Task (in progress work)

Milestone/Deliverable (Originally Planned) use for missed milestones

Milestone/Deliverable (Actual) use when met on time

FY2018FY2019FY2020

TaskQ1 (Oct-Dec)Q2 (Jan-Mar)Q3 (Apr-Jun)Q4 (Jul-Sep)Q1 (Oct-Dec)Q2 (Jan-Mar)Q3 (Apr-Jun)Q4 (Jul-Sep)Q1 (Oct-Dec)Q2 (Jan-Mar)Q3 (Apr-Jun)Q4 (Jul-Sep)

Current/Future Work

Q2: complete 3- fluid HMX model extension

Q4: complete system design/opt case study

Q3: complete condensing membrane HX model


Membrane-based 3-Fluid HMX MethodologyCurrent Model capability:● C++ CODE setup● Segment-by-segment solution● Multi-membrane panels● Water & desiccant streams can be parallel or

counter flow● Surface deflection correction (account for non-

uniform spacing between membrane panels)

Key assumptions: ● steady state ● heat conduction and vapor diffusion thru the membrane ● negligible conduction and vapor diffusion in flow stream direction ● two-layer membrane structure

Electrical analog of HT resistance across the 3-Fluid HMX

�̇�𝑚𝑣

Membrane Liquid

Desiccant Air

Td, Pd, Pd,v Ta, Pa, Pa,v

Tdm Tam

Heat Transfer Surface

Water

Tw

Tds Tws

Membrane supporting film

Membrane film

● vapor condensation within liquid desiccant


Heat Pump Design Model (HPDM)

Semi-open absorber component for membrane HPWH: Membrane-based 3-Fluid HMX component model

HPDM:Component-based system modeling platform

Slide Number 1Project SummaryTeamChallengeApproachProgressImpact – Sorption HPWH and SH heat pumpsStakeholder EngagementRemaining Project WorkSlide Number 10Slide Number 11Project BudgetProject Plan and ScheduleMembrane-based 3-Fluid HMX MethodologyHeat Pump Design Model (HPDM)

design/optimization of heat/mass exchangers (hmx) using ... · • dr. kyle gluesenkamp and dr....

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